Link-a-Pix are arguably the easiest puzzles here. overall. Even the mediums tend to be pretty easy; the ranking is usually because of the size, rather than the actual difficulty of finding paths. But there is a way of making color ones a little tougher: do one color at a time. While some connections are obvious, many of them require that nearby paths be done first. If you do all of the connections of one color before going to a different color, you often will need to mentally work out the nearby connections of other colors beforehand To make things even tougher, don't use the "check" feature at all, or at least wait until you've finished with a color before checking your work.